Effect of cyclic nucleotides on the cyanide-insensitive respiration of polymorphonuclear leucocytes

The effects of N6,O2'-dibutyryladenosine 3',5'-monophosphate (Bu2-cyclic AMP) and N2,O2'-dibutyrylguanosine 3',5'-monophosphate (Bu2-cyclic GMP) on the cyanide-insensitive respiration of guinea pig peritoneal exudate polymorphonuclear leucocytes were studied. Bu2-cyclic AMP inhibited the respiration induced both by phagocytosis of E. coli and by the interaction with trypsin-digested rat liver microsomes. The addition of theophylline gave rise to an inhibitory pattern similar to that with Bu2-cyclic AMP against both the respirations induced. On the other hand, Bu2-cyclic GMP did not affect the respiration induced by phagocytosis whereas it inhibited the respiration induced by the addition of myristic acid was inhibited by Bu2-cyclic AMP, which was similar to that with E. coli. The respiration induced by methylene blue was inhibited neither by Bu2-cyclic AMP nor by Bu2-cyclic GMP. These observations suggest that the cyanide-insensitive respiration of polymorphonuclear leucocytes may be classified into at least three types from the inhibitory pattern of cyclic AMP and cyclic GMP.